Perampanel, a selective, noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist, as adjunctive therapy for refractory partial-onset seizures: interim results from phase III, extension study 307

Redefined giant somatosensory evoked potentials: Evoked epileptic complexes of excitatory and inhibitory components

OBJECTIVE

Giant somatosensory evoked potentials (SEPs) are observed in patients with cortical myoclonus. Short-latency components (SLC), are regarded as evoked epileptic activities or paroxysmal depolarization shifts (PDSs). This study aimed to reveal the electrophysiological significance of the middle-latency component (MLC) P50 of the SEPs.

METHODS

Twenty-two patients with cortical myoclonus having giant SEPs (patient group) and 15 healthy controls were included in this study. Waveform changes in SEPs before and after perampanel (PER) treatment were evaluated in the patient group. The wide range, time-frequency properties underlying the waveforms were compared between the groups.

RESULTS

After PER treatment, SLC was prolonged and positively correlated with PER concentration, whereas MLC showed no correlation with PER concentration. Time-frequency analysis showed a power increase (156 Hz in all patients, 624 Hz in benign adult familial myoclonus epilepsy patients) underlying SLC and a power decrease (156 Hz, 624 Hz) underlying MLC in the patient group.

CONCLUSIONS

The high-frequency power increase in SLCs and decrease in MLCs clearly reflected PDS and subsequent hyperpolarization, respectively. This relationship was similar to that of interictal epileptiform discharges, suggesting that giant SEPs evoke epileptic complexes of excitatory and inhibitory components.

SIGNIFICANCE

MLCs of giant SEPs reflected inhibitory components.

Long-term treatment with Perampanel of Chinese patients with focal-onset seizures, especially in sleep-related epilepsy: a prospective real-world observational study

Background

There is currently a lack of studies examining the long-term therapeutic effectiveness of the third-generation anti-sezure medication, perampanel (PER), for focal-onset seizures (FOS), particularly in Chinese patients with sleep-related epilepsy (SRE). Additionally, the appropriate dosage, plasma concentration, and the relationship between dose and plasma concentration of PER in Chinese patients are still uncertain.

Methods

A prospective, single-center, 24-month observational study was conducted in patients diagnosed with FOS, with a focus on patients with SRE. Changes in seizure frequency from baseline, adverse events, and retention rates were analyzed at 12 and 24 months following the start of the treatment. Tolerability was evaluated based on adverse events and discontinuation profiles. PER plasma concentrations were used to assess dose-concentration-response relationships.

Results

A total of 175 patients were included (median age: 25 years; range: 4-72 years; 53. 1% males and 46.9% females), with the SRE population accounting for 49. 1% (n = 86). The patients diagnosed with SRE showed considerably higher response rates than those who did not have this diagnosis (p = 0.025, odds ratio = 3.8). Additionally, the SRE group adhered better to PER treatment (r = 0.0009). Patients with a shorter duration of epilepsy (median: 3 years; range:2-7 years) demonstrated a more favorable therapeutic response to PER (p = 0.032). Throughout the administration of maintenance doses, among the entire FOS population, the concentration of PER (C0) ranged between 101.5 and 917.4 ng/mL (median, 232.0 ng/mL), and the mean plasma concentration of PER in the responders was 292.8 ng/mL. We revealed a linear relationship between PER dose and plasma concentration, regardless of whether PER was used as monotherapy or add-on therapy. The retention rates were 77.7% and 65. 1% at 12 and 24 months, respectively. Drug-related adverse events occurred in 45.0% of the patients and were mostly manageable.

Conclusion

PER effectively reduced seizure frequency in Chinese patients with FOS, particularly in those with SRE, over a 24-month period. The treatment was well-tolerated and had a clear linear dose-plasma concentration relationship.

WRAPPER study: Real-world effectiveness and tolerability of adjunctive perampanel for people with drug-resistant epilepsy in Hong Kong

OBJECTIVE

The Prince of Wales Hospital (PWH) Real-world Analysis of People with Drug-Resistant Epilepsy (DRE) on PERampanel (WRAPPER) study assessed effectiveness and tolerability of adjunctive perampanel in people with DRE attending PWH.

METHODS

This was a prospective single-center real-world observational study involving 70 people with DRE between July 2016 and June 2021. A post hoc analysis after the initial study period of 16 weeks assessed outcomes for an extended period up to 52 weeks.

RESULTS

After 16 weeks, median dose of perampanel was 2 mg (IQR 24 mg). 50% responder rates were 40.0%, 41.5%, and 48.7% at 16, 26, and 52 weeks. Seizure freedom was 12.9%, 20.7%, and 25.6% at 16, 26, and 52 weeks. Monthly seizure frequency reduced from 3.0 (IQR 3.0-6.6) at baseline to 2.0 (IQR 2.0-6.0, p = 0.005) at 16 weeks; 2.0 (IQR 2.0-5.0, p = 0.01) at 26 weeks; and 2.0 (IQR 0.0-4.0, p = 0.018) at 52 weeks. Older age predicted 50% responders (OR 1.08, 95% CI 1.01-1.14, p = 0.048). At 16 weeks, 51.4% (36/70) had treatment-emergent adverse effects (TEAEs). Most common was seizure exacerbation at 35.7% (25/70) followed by fatigue at 15.7% (11/70). NPI-12 and ZBI scores indicated no increase in neuropsychiatric symptoms on perampanel.

SIGNIFICANCE

Low-dose 2-4 mg adjunctive perampanel for people with DRE conferred appreciable improvements in seizure reduction without significant neuropsychiatric adverse effects in the real-world setting at a tertiary center in Hong Kong and had better antiseizure effect with advancing age.

PLAIN LANGUAGE SUMMARY

This real-world study from Hong Kong found low-dose perampanel was effective and tolerable for people with drug-resistant epilepsy. Furthermore, perampanel was also potentially more effective with advancing age.

The broad-spectrum activity of perampanel: state of the art and future perspective of AMPA antagonism beyond epilepsy

Glutamate is the brain's main excitatory neurotransmitter. Glutamatergic neurons primarily compose basic neuronal networks, especially in the cortex. An imbalance of excitatory and inhibitory activities may result in epilepsy or other neurological and psychiatric conditions. Among glutamate receptors, AMPA receptors are the predominant mediator of glutamate-induced excitatory neurotransmission and dictate synaptic efficiency and plasticity by their numbers and/or properties. Therefore, they appear to be a major drug target for modulating several brain functions. Perampanel (PER) is a highly selective, noncompetitive AMPA antagonist approved in several countries worldwide for treating different types of seizures in various epileptic conditions. However, recent data show that PER can potentially address many other conditions within epilepsy and beyond. From this perspective, this review aims to examine the new preclinical and clinical studies-especially those produced from 2017 onwards-on AMPA antagonism and PER in conditions such as mesial temporal lobe epilepsy, idiopathic and genetic generalized epilepsy, brain tumor-related epilepsy, status epilepticus, rare epileptic syndromes, stroke, sleep, epilepsy-related migraine, cognitive impairment, autism, dementia, and other neurodegenerative diseases, as well as provide suggestions on future research agenda aimed at probing the possibility of treating these conditions with PER and/or other AMPA receptor antagonists.

Perampanel add-on for drug-resistant focal epilepsy

BACKGROUND

Epilepsy is one of the most common neurological disorders. Approximately 30% of people with epilepsy are considered to be drug-resistant, and usually need treatment with a combination of other antiepileptic drugs. Perampanel is a newer antiepileptic drug that has been investigated as add-on therapy for drug-resistant focal epilepsy.

OBJECTIVES

To evaluate the benefits and harms of perampanel as add-on therapy for people with drug-resistant focal epilepsy.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 20 October 2022.

SELECTION CRITERIA

We included randomised controlled trials comparing add-on perampanel with placebo.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcome was 1. 50% or greater reduction in seizure frequency. Our secondary outcomes were 2. seizure freedom, 3. treatment withdrawal due to any reason, 4. treatment withdrawal due to adverse effects, and 5.

ADVERSE EFFECTS

We used an intention-to-treat population for all primary analyses. We presented the results as risk ratios (RR) with 95% confidence intervals (CIs), except for individual adverse effects, which we reported with 99% CIs to compensate for multiple testing. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We included seven trials involving 2524 participants, all aged over 12 years. The trials were double-blind, randomised, placebo-controlled trials with treatment duration of 12 to 19 weeks. We assessed four trials at overall low risk of bias, and three trials at overall unclear risk of bias, due to risk of detection, reporting, and other biases. Compared with placebo, participants receiving perampanel were more likely to achieve a 50% or greater reduction in seizure frequency (RR 1.67, 95% CI 1.43 to 1.95; 7 trials, 2524 participants; high-certainty evidence). Compared to placebo, perampanel increased seizure freedom (RR 2.50, 95% CI 1.38 to 4.54; 5 trials, 2323 participants; low-certainty evidence) and treatment withdrawal (RR 1.30, 95% CI 1.03 to 1.63; 7 trials, 2524 participants; low-certainty evidence). Participants treated with perampanel were more likely to withdraw from treatment due to adverse effects compared to those receiving placebo (RR 2.36, 95% CI 1.59 to 3.51; 7 trials, 2524 participants; low-certainty evidence). A higher proportion of participants receiving perampanel reported one or more adverse effects when compared to participants who received placebo (RR 1.17, 95% CI 1.10 to 1.24; 7 trials, 2524 participants; high-certainty evidence). Compared with placebo, participants receiving perampanel were more likely to experience ataxia (RR 14.32, 99% CI 1.09 to 188.31; 2 trials, 1098 participants; low-certainty evidence), dizziness (RR 2.87, 99% CI 1.45 to 5.70; 7 trials, 2524 participants; low-certainty evidence), and somnolence (RR 1.76, 99% CI 1.02 to 3.04; 7 trials, 2524 participants). Subgroup analysis indicated that a larger proportion of participants who received perampanel at a dose of 4 mg/day (RR 1.38, 95% CI 1.05 to 1.83; 2 trials, 710 participants), 8 mg/day (RR 1.83, 95% CI 1.51 to 2.22; 4 trials, 1227 participants), or 12 mg/day (RR 2.38, 95% CI 1.86 to 3.04; 3 trials, 869 participants) achieved a 50% or greater reduction in seizure frequency compared to placebo; however, treatment with perampanel 12 mg/day also increased treatment withdrawal (RR 1.77, 95% CI 1.31 to 2.40; 3 trials, 869 participants).

AUTHORS' CONCLUSIONS

Add-on perampanel is effective at reducing seizure frequency and may be effective at maintaining seizure freedom for people with drug-resistant focal epilepsy. Although perampanel was well-tolerated, there was a higher proportion of treatment withdrawals with perampanel compared with placebo. Subgroup analysis suggested that 8 mg/day and 12 mg/day are the most efficacious perampanel doses; however, the use of 12 mg/day would likely increase the number of treatment withdrawals. Future research should focus on investigating the efficacy and tolerability of perampanel with longer-term follow-up, as well as exploring an optimal dose.

Long-term efficacy and safety of perampanel as a first add-on therapy in patients with focal epilepsy: Three-year extension study

PURPOSE

We investigated the long-term efficacy and safety of perampanel as a first add-on therapy in patients with focal epilepsy.

METHODS

This retrospective study represented the 3-year extension phase of a multicenter, open-label, phase 4, prospective study of perampanel as a first add-on therapy in patients with focal epilepsy. Seizure and safety outcomes were assessed annually from the start of the extension study, and the retention rate was calculated from the start of perampanel exposure in the original study.

RESULTS

The 50% responder and seizure freedom rates were 84.8% and 58.7%, respectively, during the third year and 71.7% and 32.6%, respectively, during the entire 3-year period of the extension study. The 1-, 2-, and 3-year retention rates were 62.5%, 53.1%, and 52.1%, respectively. Efficacies were higher in patients that were aged >55 years, male, and receiving ≤4 mg of perampanel. Perampanel was generally well tolerated; 47.3% of patients experienced at least one adverse event during the 3 years of extension (46 adverse events (AEs) in 35 patients). The most common AEs were dizziness (33.8%), somnolence (5.4%), anger (4.1%), and irritability (4.1%). AEs were resolved with perampanel dose reduction or discontinuation in 10 (13.5%) and 12 (16.2%) patients, respectively.

CONCLUSION

Long-term treatment with perampanel as a first add-on therapy did not raise new safety signals in patients with focal epilepsy. Especially at low perampanel doses (≤4 mg/day), sustained improvement in seizure control was achieved, which could potentially avoid adverse drug reactions.

Perampanel-Induced Psychosis in a Young Woman: A Case Report

OBJECTIVES

A case of perampanel-induced psychosis in a young woman is reported, a side effect that has only rarely been reported in the literature.

METHODS

We describe a case of a young woman with epilepsy and no psychiatric history with perampanel-associated altered behavior and psychotic symptoms, requiring hospitalization in an acute psychiatry ward. We also provide a literature review on the possible neurobiological pathways implicated.

RESULTS

Perampanel is believed to block a small proportion of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor current, retarding epileptiform discharges while sparing most normal synaptic transmission. Most common adverse events are related to central nervous system (including dizziness, drowsiness, blurred vision and imbalance) and psychiatric symptoms have been reported.

CONCLUSIONS

The biological vulnerability to psychiatric and behavioral adverse reactions of antiepileptic drugs is multifactorial and different mechanisms and clinical predisposing factors may interact. For this reason, patients starting these antiseizure drugs need long-term and comprehensive clinical monitoring.

Perampanel effectiveness and tolerability in patients with epilepsy at long-term follow-up

INTRODUCTION

The main of the present study was to assess the effectiveness and tolerability of perampanel (PER) in association with 1 or 2 concomitant antiseizure medications (ASMs) in patients with epilepsy throughout a follow-up period of 24 months or longer in a real-world setting.

METHODS

This retrospective, observational, multi-center study collected data from both underage (<18 years old) and adult patients who had started PER in association with 1 or 2 ASMs. Only patients who had started PER and were followed up for at least 24 months were included. Response to treatment was analyzed at the 24-, 36-, and 48-month visits by considering the last visit undergone by patients. Subgroup analyses were performed according to age, gender, and epilepsy type and patients were categorized following PER treatment in concomitance with 1 or 2 ASMs to evaluate the factors affecting the achievement of seizure freedom (SF) at the 24-month FU.

RESULTS

Ninety-four patients were included (mean age 36.89 years; 51.1% female). At the 24-month follow-up visit, 90 (95.74%) patients were still receiving PER concomitantly with 1 or 2 ASMs. The mean PER dose was 6.02 mg/day and SF was achieved by 33 (35.1%) patients. A significantly higher SF rate was found in patients who had started PER with only 1 ASM when compared to those who had started PER with 2 concomitant ASMs. Effectiveness was maintained also in the subgroups of patients with a 36- or 48-month follow-up visit. Adult patients had a higher final daily dosage of PER than underage patients. Logistic regression found that the lowest number of previously failed ASMs was associated with a higher SF rate (p = 0.036).

CONCLUSION

Perampanel demonstrated a good effectiveness in association with 1 or 2 ASMs in both pediatric and adult patients, without having to use a high dose of the drug. The possibility to present SF was higher when PER was added early. Finally, the maintenance of effectiveness was observed also in the subgroups of patients with a follow-up of 36 and 48 months.

Perampanel and Visuospatial Skills in Children With Epilepsy

Introduction: Perampanel (PER) is a non-competitive AMPA glutamate receptor antagonist approved for focal and generalized seizures as add-on therapy. PER does not seem to negatively affect the cognitive profile in children and adolescents, but its influence on visuospatial abilities is still to be assessed. The aim of our study was to assess visuospatial skills through a standardized neuropsychological evaluation in adolescents taking PER for 12 months.

Methods: Our sample included 46 adolescents aged 12–18 years with focal and generalized drug-resistant epilepsy already in therapy with one or two antiseizure medications. Changes in visuospatial perception and memory were assessed by the Rey–Osterrieth Complex Figure Test at baseline (before taking PER) and after 12 months of pharmacological treatment. Executive functions and non-verbal intelligence were also assessed at baseline.

Results: After 12 months of PER therapy, the mean scores on the Rey–Osterrieth Complex Figure Test remained almost unchanged for both visuospatial perception and visuospatial memory skills. At baseline, visuospatial memory was related to executive function, and visuospatial perception was related to executive function and non-verbal intelligence.

Conclusions: Adjunctive treatment with PER did not negatively affect visuospatial skills. No adverse event effects have been reported after 12 months of follow-up, and this suggests a good tolerability in the middle-to-long term.

Positive and negative effects of perampanel treatment on psychiatric and behavioral symptoms in adult patients with epilepsy

PURPOSES

The purpose of the study was to investigate the positive and negative effects of perampanel (PER) treatment on the psychiatric and behavioral symptoms in patients with epilepsy and to evaluate factors associated with the psychiatric and behavioral changes caused by PER.

METHODS

We retrospectively examined medical records of patients with epilepsy treated with PER in the Department of Psychiatry, Epilepsy Center, Nishiniigata Chuo National Hospital. Multiple regression analyses were performed with the psychiatric and behavioral prognoses as dependent variables and clinical characteristics of the patients as independent variables.

RESULTS

Thirty-two of 135 patients (23.7%) had psychiatric and behavioral deterioration after the initiation of PER, whereas 22 patients (16.3%) showed improvement in psychiatric and behavioral symptoms after PER administration. Etiology of structural abnormalities, concomitant use of nitrazepam, and comorbidities of irritability and depression were significantly associated with increasing incidence of psychiatric and behavioral deterioration. Concomitant use of carbamazepine was significantly associated with decreasing incidence of psychiatric and behavioral deterioration. Suppression of awareness-impaired seizures by PER, concomitant use of carbamazepine, and comorbidities of insomnia, anxiety, and amnesia were significantly associated with an increasing incidence of psychiatric and behavioral improvement. Improvements in psychiatric symptoms by PER were associated with a reduction in the use of psychotropic drugs. In particular, about 1/4 of benzodiazepines had been discontinued.

CONCLUSIONS

Perampanel therapy may aggravate or even ameliorate psychiatric and behavioral symptoms in patients with epilepsy. The psychiatric and behavioral prognoses after administration of PER vary depending on the type of psychiatric and behavioral comorbidities in patients with epilepsy. Psychiatric and behavioral symptoms may improve in patients with successful suppression of seizures by PER. Additionally, combination therapy consisting of PER and carbamazepine may be associated with good outcomes of psychiatric and behavioral symptoms in patients with epilepsy.

Retention Rate and Efficacy of Perampanel with a Slow Titration Schedule in Adults

RATIONALE

The manufacturer of perampanel (PER) suggests an initial adult dose of 2-4 mg/day and an upward dose titration of 2 mg at no more frequently than 1- or 2-week intervals when used with enzyme-enhancing antiepileptic drugs (AEDs) or nonenzyme-enhancing AEDs, respectively. The general practice in our clinic is an initial dose of PER 2 mg/day and titrated by 2 mg/4 weeks to an initial target of 6 mg/day.

METHODS

Retrospective chart audit of patients starting PER in an adult epilepsy clinic between September 2013 and November 2016 with at least one 6-month follow-up visit was reviewed. Data collection included patient demographics, seizure characteristics, past and concurrent therapy, monthly seizure frequency before PER and at 6-month visit, and characteristics of PER discontinuation. Efficacy of treatment was assessed with the Engel classification and 50% responder rate.

RESULTS

N = 102 patients; mean age = 40 years and 54% females. Focal onset seizures 85%, generalized 13%, and unknown 2%. Median prior AED exposure = 6 (range 3-20); median concomitant AED use = 2 (range 1-5). Follow-up range was 6-37 months. The median seizure frequency/month prePER treatment was 6 (range 0-30) for focal onset seizures and 1 (range 0-6) for generalized seizures. The retention rate amongst all patients at 6 months was 78.4%. At 6-month follow-up, 36% of all patients achieved Engel class I (seizure freedom) (30.7% of patients with focal onset seizures and 63.6% with generalized epilepsy). The 50% responder rate was 52% and 82% for focal and generalized epilepsy, respectively.

CONCLUSION

PER has a good retention rate when titrated slowly and thus encouraging seizure freedom results in an otherwise medically refractory epilepsy population.

First add-on perampanel for focal-onset seizures: An open-label, prospective study

Objectives

This study aimed to determine the efficacy and safety of perampanel added to monotherapy in patients with focal‐onset seizures, with or without secondarily generalized tonic‐clonic seizures.

Materials & Methods

In this multicentre, open‐label trial, enrolled patients were treated with perampanel monotherapy. During a 12‐week titration period, perampanel was incrementally increased by 2 mg/d over ≥2‐week intervals. Patients then entered a 24‐week maintenance period. The primary objective was to investigate the 50% responder rate in total seizure frequency, with 75% and 100% responder rates as secondary objectives. Treatment‐emergent adverse events (TEAEs) and adverse drug reactions were recorded. A post hoc analysis was performed to investigate the effect of titration speed and different concomitant AEDs on the efficacy and safety of perampanel.

Results

Of the 85 patients analysed, seizure reductions of 50%, 75% and 100% were observed in 80.0% (95% confidence interval [CI]: 69.9‐87.9), 71.8% (95% CI: 61.0‐81.0) and 47.1% (95% CI: 36.1‐58.2) during the maintenance period, respectively. The 50%, 75% and 100% response rates in patients with secondarily generalized tonic‐clonic seizures were 87.5% (95% CI: 61.7‐98.5), 87.5% (95% CI: 61.7‐98.5) and 75.0% (95% CI: 47.6‐92.7), respectively. The most common TEAEs were dizziness (50.0%), somnolence (9.8%) and headache (8.8%). The efficacy outcomes and safety profile of perampanel were more favourable with slow titration and relatively consistent when stratified by concomitant AEDs.

Conclusions

Perampanel was effective and well tolerated as a first add‐on to monotherapy in patients with focal‐onset seizures, with or without secondarily generalized seizures.

Perampanel tolerability in children and adolescents with focal epilepsy: Effects on behavior and executive functions

OBJECTIVES

Perampanel (PER) is a noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonist recently approved for focal and generalized epilepsies as an add-on therapy. It is well tolerated and effective as treatment of various pediatric epilepsy syndromes; PER does not seem to negatively affect the cognitive profile of children and adolescents, but its influence on executive functions is still to be assessed.

METHODS

Our sample included 37 children aged 12-18 years, with focal pharmacoresistant epilepsy already in therapy with 2 or 3 antiepileptic drug (AED); PER was added with 1 mg/week increments up to a dose of 2-4 mg/day. Changes in executive functions were assessed by the EpiTrack Junior test. Emotional and behavioral aspects were evaluated through the interview for parents Child Behavior Checklist (CBCL). Both tests were performed before taking PER and after 6 and 12 months of treatment.

RESULTS

After 12 months of PER in 22/30 patients, global score of the EpiTrack Junior test remained almost unchanged; in 7/30 patients, this score improved. The CBCL did not show significant changes in emotional or behavioral problems.

CONCLUSIONS

Adjunctive treatment with PER did not negatively affect executive functions that could also be improved. No emotional/behavioral negative effects have been reported, and this suggests a good tolerability in the middle/long term.

Effectiveness and safety of perampanel as early add-on treatment in patients with epilepsy and focal seizures in the routine clinical practice: Spain prospective study (PERADON)

OBJECTIVE

Perampanel (PER) has been shown to be effective as an adjunctive therapy for controlling refractory focal-onset seizures (FOS). However, the information as early add-on for the treatment of FOS in the clinical practice is still scarce and must be further assessed.

METHODS

An observational prospective study was conducted to evaluate the effectiveness of early add-on PER, assessed as 50% responders (seizure frequency reduced by at least 50% during the last 3 months as compared with baseline) rate at 6 and 12 months, in patients with FOS in the routine clinical practice of Spain.

RESULTS

One hundred and thirteen patients (mean age: 40.3 years, 51.3% male) with FOS received PER as early add-on (1st add-on: 37.2% and 2nd: 62.8%) for a mean exposure of 11 months (mean PER dose: 6.3 mg/day at month 12). At 6 months, 50.4% and 20.4% of the patients were responders and seizure-free (respectively) relative to baseline (3 months prior to PER initiation), and at 12 months, 68.1% and 26.5% of the patients were responders and seizure-free (respectively), relative to baseline (3 months prior to PER initiation). The retention rate at 6 and 12 months was 83.2% and 80.5%, respectively. The percentage of seizure-free patients at 12 months was significantly (p = 0.033) higher when PER was added as first vs. second add-on. The number of concomitant antiepileptic drugs (AEDs) was significantly reduced from baseline to 6 and 12 months (p = 0.001). Treatment was simplified in 23.9% of patients at the end of the observation period. Drug-related adverse events (AEs), most mild or moderate, were reported in 30.1% of patients, with irritability (8%) and dizziness (7.1%) as the most frequent ones.

CONCLUSIONS

This is the first observational, prospective study to evaluate efficacy and safety of early adjunctive treatment with PER in patients with focal epilepsy at 12 months. Perampanel demonstrated a good efficacy and safety profile when used at a median dose of 6 mg/day, regardless of the combination with other AEDs. Adverse events were mild or moderate, with dizziness being the most frequent one.

Low-dose perampanel improves refractory cortical myoclonus by the dispersed and suppressed paroxysmal depolarization shifts in the sensorimotor cortex

OBJECTIVE

To elucidate the effects of perampanel (PER) on refractory cortical myoclonus for dose, etiology and somatosensory-evoked potential (SEP) findings.

METHODS

We examined 18 epilepsy patients with seizure and cortical myoclonus. Based on data accumulated before and after PER treatment, correlations among clinical scores in myoclonus and activities of daily life (ADL); early cortical components of SEP; and PER blood concentration, were analyzed.

RESULTS

PER (mean dose: 3.2 ± 2.1 mg/day) significantly improved seizures, myoclonus and ADL and significantly decreased the amplitude of and prolonged latency of giant SEP components. The degree of P25 and N33 prolongations (23.8 ± 1.6 to 24.7 ± 1.7 ms and 32.1 ± 4.0 to 33.7 ± 3.4 ms) were significantly correlated with improved ADL score (p = 0.019 and p = 0.025) and blood PER concentration (p = 0.011 and p = 0.025), respectively.

CONCLUSIONS

Low-dose PER markedly improved myoclonus and ADL in patients with refractory cortical myoclonus. Our results suggest that SEP, particularly P25 latency, can be used as a potential biomarker for assessing the objective effects of PER on intractable cortical myoclonus.

SIGNIFICANCE

In this study, PER lessened the degree of synchronized discharges in the postsynaptic neurons in the primary motor cortex.

Clinical Experience with Perampanel in Intractable Focal Epilepsy Over 12 Months of Follow-Up

Background and Purpose

There are only limited studies on perampanel (PER), one of the latest antiepileptic drug. This study aimed to evaluate the long-term efficacy and tolerability of perampanel as an add-on therapy in patients with intractable focal epilepsy.

Methods

The medical records of 97 patients (age, 12-30 years) were retrospectively reviewed and analyzed. The patients had been diagnosed with focal epilepsy, treated with PER, and regularly followed up over 12 months.

Results

All patients had uncontrolled seizures despite treatment with two or more antiepileptic drugs. The mean age of seizure onset was 5.2 years (range, 0-17.0). PER was first prescribed at an average age of 15.7 years (range, 12.0-25.3), and mean follow-up duration after PER initiation was 15.9 months (range, 12-20). The responder rate was 41.7%, with over 75% seizure reduction obtained in 11 cases (15.3%), including three seizure-free cases (4.2%). The retention rates at 3, 6, 12, and 18 months of follow-up were 82.5% (80/97), 72.1% (70/97), 60.8% (59/97), and 37.5% (6/16), respectively. Forty-four patients (44/97, 45.4%) discontinued PER, because of treatment-related adverse events in 20 (20.6%) and no efficacy in 24 (24.7%). Treatment-related adverse events were reported by 52 patients (53.6%). The most common adverse event was somnolence or lethargy, reported by 17 patients (17/97, 23%), followed by dizziness (15/97, 20%) and psychological problems such as aggressiveness or irritability (15/97, 20%). Thirty-three patients (33/52, 63.4%) showed their first adverse symptom for 2 or 4 mg/day of PER.

Conclusions

PER would be an effective therapeutic option for patients with intractable focal epilepsy. However, careful monitoring of adverse events is essential from treatment initiation, with particular attention to psychological problems in adolescents and young adults.

Retrospective study of perampanel efficacy and tolerability in myoclonic seizures

OBJECTIVES

Perampanel is an antiepileptic drug (AED) approved for add-on treatment of focal seizures (with or without generalization) and primary generalized tonic-clonic (GTC) seizures. Our objective was to explore the effectiveness and tolerability of adjunctive perampanel in patients with drug-resistant myoclonic seizures, after failure of other AEDs.

MATERIALS AND METHODS

Retrospective, multicenter, observational study. Data were collected from individual patient clinical files and analysed using appropriate descriptive statistics and inferential analyses.

RESULTS

Data are reported for 31 patients with mean age 36.4 years, who had an average epilepsy duration of 18 years, previously taken an average of 5.03 AEDs, and were taking an average of 2.4 AEDs on perampanel initiation. Patients exhibited myoclonic, GTC, absence, tonic and focal seizures, and most had associated cognitive decline and/or ataxia. Median time on perampanel was 6 months, most common dose was 6 mg, and overall retention rate was 84%. The responder rate for myoclonic seizures was defined via reduction of days with myoclonic seizures per month. At 6 months, 15 (48.4%) of the 31 patients were classed as myoclonic seizure responders, 10 (32.3%) were myoclonic seizure free, and 39% saw improvements in functional ability. Of 17 patients with GTC seizures at baseline, 9 (53%) were responders at 6 months, and 8 (47.1%) were seizure free. The most frequent side effects were psychiatric disorders, instability, dizziness and irritability, and mostly resolved with dose reduction. Five patients discontinued perampanel due to side effects.

CONCLUSIONS

Perampanel caused clinically meaningful improvements in patients with drug-resistant myoclonic seizures. It was generally well tolerated, but psychiatric and neurological side effects sometimes required follow-up and dose reduction.

Perampanel in routine clinical use in idiopathic generalized epilepsy: The 12-month GENERAL study

OBJECTIVE

To analyze the effectiveness and tolerability of perampanel across different seizure types in routine clinical care of patients with idiopathic generalized epilepsy (IGE).

METHODS

This multicenter, retrospective, 1-year observational study collected data from patient records at 21 specialist epilepsy units in Spain. All patients who were aged ≥12 years, prescribed perampanel before December 2016, and had a confirmed diagnosis of IGE were included.

RESULTS

The population comprised 149 patients with IGE (60 with juvenile myoclonic epilepsy, 51 generalized tonic-clonic seizures [GTCS] only, 21 juvenile absence epilepsy, 10 childhood absence epilepsy, 6 adulthood absence epilepsy, and one Jeavons syndrome). Mean age was 36 years. The retention rate at 12 months was 83% (124/149), and 4 mg was the most common dose. At 12 months, the seizure-free rate was 59% for all seizures (88/149); 63% for GTCS (72/115), 65% for myoclonic seizures (31/48), and 51% for absence seizures (24/47). Seizure frequency was reduced significantly at 12 months relative to baseline for GTCS (78%), myoclonic (65%), and absence seizures (48%). Increase from baseline seizure frequency was seen in 5.2% of patients with GTCS seizures, 6.3% with myoclonic, and 4.3% with absence seizures. Perampanel was effective regardless of epilepsy syndrome, concomitant antiepileptic drugs (AEDs), and prior AEDs, but retention and seizure freedom were significantly higher when used as early add-on (after ≤2 prior AEDs) than late (≥3 prior AEDs). Adverse events were reported in 50% of patients over 12 months, mostly mild or moderate, and irritability (23%), somnolence (15%), and dizziness (14%) were most frequent.

SIGNIFICANCE

In routine clinical care of patients with IGE, perampanel improved seizure outcomes for GTCS, myoclonic seizures, and absence seizures, with few discontinuations due to adverse events. This is the first real-world evidence with perampanel across different seizure types in IGE.

A Review of the New Antiepileptic Drugs for Focal-Onset Seizures in Pediatrics: Role of Extrapolation

Most antiepileptic drugs (AEDs) receive regulatory approval for children years after the drug is available in adults, encouraging off-label use of the drug in children and hindering attempts to obtain quality pediatric data in controlled trials. Extrapolating adult efficacy data to pediatrics can reduce the time between approval in adults and that in children. To extrapolate efficacy from adults to children, several assumptions must be supported, such as (1) a similar disease progression and response to interventions in adults and children, and (2) similar exposure response in adults and children. The Pediatric Epilepsy Academic Consortium for Extrapolation (PEACE) addressed these assumptions in focal-onset seizures (FOS), the most common seizure type in both adults and children. PEACE reviewed the biological and clinical evidence that supported the assumptions that children with FOS have a similar disease progression and response to intervention as adults with FOS. After age 2 years, the pathophysiological underpinnings of FOS and the biological milieu in which seizures are initiated and propagated in children, seizure semiology, electroencephalographic features, etiology and AED response to FOS in children are similar to those in adults with FOS. PEACE concluded that extrapolation of efficacy data in adults to pediatrics in FOS is supported by strong scientific and clinical evidence. However, safety and pharmacokinetic (PK) data cannot be extrapolated from adults to children. Based on extrapolation, eslicarbazepine is now approved for children with FOS, down to age 4 years. Perampanel, lacosamide and brivaracetam are now undergoing PK and safety studies for the purposes of extrapolation down to age 2 or 4 years. When done in conjunction with PK and safety investigations in children, extrapolation of adult data from adults to children can reduce the time delay between approval of effective and safe AEDs in adults and approval in children.

AMPA receptors and perampanel behind selected epilepsies: current evidence and future perspectives

INTRODUCTION

The alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are the major mediators of glutamate-mediated excitatory neurotransmission, and are critical for synchronization and spread of epileptic activity. Areas covered: AMPA receptor antagonists have been also developed as antiepileptic drugs and perampanel (PER) is the first highly selective, non-competitive AMPA-type glutamate receptor antagonist that is available on the market. It is approved as adjunctive therapy for the treatment of partial-onset seizures with or without secondary generalization, and for primary generalized tonic-clonic seizures in idiopathic generalized epilepsy, in patients aged ≥ 12 years. This article reviews the role of AMPA receptors in the neuronal hyperexcitability underlying epilepsy, the mechanism of action and clinical experience on the anti-seizure activity of PER. Moreover, the rationale for targeting AMPA receptor in specific epileptic disorders, including brain tumor-related epilepsy, mesial temporal lobe epilepsy with/without hippocampal sclerosis, and status epilepticus is evaluated. Finally, the pharmacological rationale for the development of AMPA receptor antagonists in other neurological disorders beyond epilepsy is considered. Expert opinion: Further research aimed at better understanding the pharmacology and blocking mechanism of PER and other AMPA receptor antagonists will drive future development of therapeutic agents that target epilepsy and other neurological diseases.

Spotlight on perampanel in the management of seizures: design, development and an update on place in therapy

Purpose

Perampanel is a first-in-class antiepileptic medication approved for the treatment of partial (focal) seizures, and as adjunctive treatment for primarily generalized tonic–clonic seizures. The pharmacology, efficacy data, adverse-effect profile, pharmacokinetics and place in therapy are reviewed.

Summary

Perampanel is indicated for use in patients with epilepsy who are 12 years of age or older. It is the first medication designed specifically to be a non-competitive antagonist at post-synaptic α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors. Efficacy in refractory seizures has been established, and ongoing efficacy demonstrated by post-marketing data. The drug is completely absorbed, and exhibits a half-life that allows for once-daily administration in doses up to 12 mg/day. Drug interactions are minimal, but increased doses may be necessary when given with strong inducers of cytochrome P450 enzymes, including when perampanel is co-administered with other antiepileptics that exhibit this property. The most common adverse effects noted in both clinical trials and post-marketing are dizziness and somnolence. Psychiatric and behavioral adverse events have been documented in both adult and pediatric patients, including those with no corresponding diagnostic history.

Conclusion

Perampanel is a novel adjunctive antiepileptic medication that is an effective option for adolescents and adults with partial seizures, and primarily generalized tonic–clonic seizures uncontrolled with other medications.

The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs

Epilepsy is a neurologic disorder affecting approximately 50 million people worldwide, or about 0.7% of the population [1]. Thus, the use of anticonvulsant drugs in the treatment of epilepsy is common and widespread. There are three generations of anticonvulsant drugs, categorized by the year in which they were developed and released. The aim of this review is to discuss the pharmacokinetics, drug-drug interactions, and adverse events of the third generation of anticonvulsant drugs. Where available, overdose data will be included. The pharmacokinetic properties of third-generation anticonvulsant drugs include relatively fewer drug-drug interactions, as well as several unique and life-threatening adverse events. Overdose data are limited, so thorough review of adverse events and knowledge of drug mechanism will guide expectant management of future overdose cases. Reporting of these cases as they occur will be necessary to further clarify toxicity of these drugs.

A human PET study of [11C]HMS011, a potential radioligand for AMPA receptors

Background

α-Amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor is a primary mediator of fast glutamatergic excitatory signaling in the brain and has been implicated in diverse neuropsychiatric diseases. We recently developed a novel positron emission tomography (PET) ligand, 2-(1-(3-([¹¹C]methylamino)phenyl)-2-oxo-5-(pyrimidin-2-yl)-1,2-dihydropyridin-3-yl) benzonitrile ([¹¹C]HMS011). This compound is a radiolabelled derivative of perampanel, an antiepileptic drug acting on AMPA receptors, and was demonstrated to have promising in vivo properties in the rat and monkey brains. In the current study, we performed a human PET study using [¹¹C]HMS011 to evaluate its safety and kinetics.

Four healthy male subjects underwent a 120-min PET scan after injection of [¹¹C]HMS011. Arterial blood sampling and metabolite analysis were performed to obtain parent input functions for three of the subjects using high-performance liquid chromatography. Regional distribution volumes (V_Ts) were calculated based on kinetic models with and without considering radiometabolite in the brain. The binding was also quantified using a reference tissue model with white matter as reference.

Results

Brain uptake of [¹¹C]HMS011 was observed quickly after the injection, followed by a rapid clearance. Three hydrophilic and one lipophilic radiometabolites appeared in the plasma, with notable individual variability. The kinetics in the brain with apparent radioactivity retention suggested that the lipophilic radiometabolite could enter the brain. A dual-input graphical model, an analytical model designed in consideration of a radiometabolite entering the brain, well described the kinetics of [¹¹C]HMS011. A reference tissue model showed small radioligand binding potential (BP*_ND) values in the cortical regions (BP*_ND = 0–0.15). These data suggested specific binding component of [¹¹C]HMS011 in the brain.

Conclusions

Kinetic analyses support some specific binding of [¹¹C]HMS011 in the human cortex. However, this ligand may not be suitable for practical AMPA receptor PET imaging due to the small dynamic range and metabolite in the brain.

Electronic supplementary material

The online version of this article (doi:10.1186/s13550-017-0313-0) contains supplementary material, which is available to authorized users.

Electroencephalographic, cognitive, and neurochemical effects of LY3130481 (CERC-611), a selective antagonist of TARP-γ8-associated AMPA receptors

6-[(1S)-1-[1-[5-(2-hydroxyethoxy)-2-pyridyl]pyrazol-3-yl]ethyl]-3H-1,3-benzothiazol-2-one (LY3130481 or CERC-611) is a selective antagonist of AMPA receptors containing transmembrane AMPA receptor regulatory protein (TARP) γ-8. This molecule has been characterized as a potent and efficacious anticonvulsant in an array of acute and chronic epilepsy models in rodents. The present set of experiments was designed to assess the effects of LY3130481 on the electroencephelogram (EEG), cognitive function, and neurochemical outflow. LY3130481 disrupted food-maintained responding in rats and spontaneous alternation in a Y-maze in mice. In rat fear conditioning, LY3130481 caused a deficit in trace (hippocampal-dependent), but not in delay fear conditioning. Although these effects on cognitive performances were observed, the known cognitive-impairing anticonvulsant, topiramate, did not always produce deficits under these assay conditions. LY3130481 produced modest increases in wake times in rats. In addition, LY3130481 was able to attenuate some impairing effects of standard antiepileptic drugs. The motor-impairing effects of the lacosamide were attenuated by LY3130481 as was the decrease in non-rapid-eye movement sleep induced by carbamazepine. Evaluation of the effect of LY3130481 on neurotransmitter and metabolite efflux in the rat medial prefrontal cortex, using in vivo microdialysis, revealed significant increases in the pro-cognitive and wake-promoting neurotransmitters, histamine and acetylcholine, as well as in serotonin, telemethylhistamine, 5-HIAA, HVA and MHPG. LY3130481 thus presents a novel behavioral profile that will have to be evaluated in patients to fully appreciate its implications for therapeutics. LY3130481 is currently under clinical development as CERC-611 as an antiepileptic.

Current role of perampanel in pediatric epilepsy

Perampanel is among the latest AEDs approved, indicated for the treatment of partial-onset seizures with or without secondary generalization, and for primary generalized tonic-clonic seizures, in patients aged 12 years and older. This paper summarizes the clinical recommendations on the current role of perampanel in the treatment of pediatric epilepsies and future directions for research. The optimal dosage should be comprised between 4 and 12 mg/day, with 8 mg/day being the most common dosage used. The rate and severity of adverse events, including psychiatric symptoms, can be decreased by starting at low doses, and titrating slowly. Overall, perampanel presents an acceptable risk/benefit ratio, but special caution should be made to the risk of seizure aggravation and behavioral problems. The favorable cognitive profile, the ease of use of the titration scheme and the once-daily formulation offer advantage over other AEDs and make this drug particularly suitable for adolescent population. Perampanel is a welcome addition to the armamentarium of the existing AEDs, as it represents a new approach in the management of epilepsy, with a novel mechanism of action and a potential to have a considerable impact on the treatment of adolescents with epilepsy.

Tolerability and efficacy of perampanel in children with refractory epilepsy

AIM

There are few reports on the tolerability and efficacy of perampanel, a new antiepileptic drug with a novel mechanism of action, in children and adolescents. We aimed to describe our experience with perampanel add-on and mono-therapy in children with refractory epilepsy.

METHOD

Computerized medical records of children treated with perampanel in the paediatric neurology clinic from December 2012 to October 2015 were reviewed.

RESULTS

Twenty-four children treated with perampanel (15 females, 9 males) aged 1 year 6 months to 17 years (mean 10y, standard deviation [SD] 4y 5mo) were identified. Adverse events were more common in children aged 12 years or older (89%) compared to younger children (53%), and were mainly behavioural. Ten (42%) children had 50 per cent or higher seizure reduction, two (8%) children had 33 per cent seizure reduction, and seizures were less severe in one (4%) child. Perampanel was discontinued in 13 (54%) children mostly due to adverse events. The mean duration of follow-up in the remaining 11 children was 8.1 months (SD 5.2) (range 1.3-17mo).

INTERPRETATION

Perampanel is associated with a relatively high rate of behavioural adverse events mostly in adolescents with refractory epilepsy.

Perampanel as add-on treatment in refractory focal epilepsy. The Dianalund experience

BACKGROUND

Perampanel (PER) is an antagonist of AMPA receptors that has been approved for adjunctive treatment of partial-onset seizures.

AIMS

To evaluate effectiveness and safety of PER as add-on treatment in patients with severely refractory focal epilepsy.

METHODS

PER was introduced as add-on treatment in 22 consecutive patients with drug-resistant focal epilepsy. PER was started with 2 mg/day at bedtime and was up-titrated by 2 mg/day every 2-4 weeks.

RESULTS

All patients suffered from severely refractory focal epilepsy (86% took 2 or more AEDs prior PER initiation; 40% had been submitted to surgery or were surgery candidates; 7 had VNS). After 12 months since PER initiation, the retention rate was 54.5% and the responder rate was 27.2%, including 9.1% seizure-free patients. Mean PER dose in the responders was 8 mg/day (range 4-10). Most common side effects were tiredness, behavioral changes (primarily aggressivity), dizziness and were reported in 59.1% of patients, leading to PER discontinuation in 31.8% of subjects.

CONCLUSIONS

PER as add-on treatment can achieve clinically meaningful improvement in patients suffering from severely refractory focal epilepses. Further studies are warranted to explore the tolerability profile, with particular focus on psychiatric adverse events.

Review of clinical studies of perampanel in adolescent patients

AIM

To assess the clinical trial and real-world data for adjunctive perampanel in adolescents and develop consensus recommendations to guide the use of perampanel in this population in clinical practice.

METHODS

In May 2015, 15 epilepsy experts attended a Consensus Development Meeting to assess the clinical trial data for perampanel, specific to the adolescent age group (12-17 years) and develop consensus treatment recommendations.

RESULTS AND DISCUSSION

Analysis of the adolescent subgroup data of three pivotal placebo-controlled, double-blind, phase 3 trials investigating perampanel in patients with ongoing focal epileptic seizures despite receiving one to three antiepileptic drugs found that perampanel 4-12 mg was superior to placebo. The tolerability profile of perampanel was generally acceptable. Adolescent patients receiving long-term treatment with perampanel in an open-label extension study maintained improvements in seizure control compared with baseline, with a favorable risk-benefit profile. A phase 2 study showed that perampanel had no clinically important effects on cognitive function, growth, and development.

CONCLUSION

Perampanel is a welcome addition to the armamentarium of existing antiepileptic drugs as it represents a new approach in the management of epilepsy, with a novel mechanism of action, and the potential to have a considerable impact on the treatment of adolescents with epilepsy.

New antiepileptic drugs: focus on ezogabine, clobazam, and perampanel

Ezogabine, clobazam, and perampanel are among the newest antiseizure drugs approved by the Food and Drug Administration between 2011 and 2012. Ezogabine and perampanel are approved for adjunctive treatment of partial epilepsy. Perampanel is also approved for adjunctive treatment of primary generalized tonic–clonic seizures. Ezogabine and perampanel have novel mechanisms of action. Ezogabine binds to voltage-gated potassium channels and increases the M-current thereby causing membrane hyperpolarization. Perampanel is a selective, non-competitive 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid receptor antagonist, which reduces neuronal excitation. Clobazam has been used worldwide since the 1970s and is approved for adjunctive treatment of seizures associated with Lennox-Gastaut syndrome. Clobazam is the only 1,5-benzodiazepine currently in clinical use, which is less sedating than the commonly used 1,4-benzodiazepines. Phase III multicenter, randomized, double-blind, placebo-controlled trials demonstrated efficacy and good tolerability of these 3 new antiepileptic drugs. These drugs represent a welcome addition to the armamentarium of practitioners, but it remains to be seen how they will affect the landscape of pharmacoresistant epilepsy.

Impact of perampanel on pharmacokinetics of concomitant antiepileptics in patients with partial-onset seizures: pooled analysis of clinical trials

Aims

To evaluate the impact of perampanel and demographics on clearance of concomitant antiepileptic drugs (AEDs), in patients with refractory partial‐onset seizures.

Methods

Pooled data from three Phase III clinical studies with adjunctive perampanel were used. Blood samples for evaluation of 11 concomitant AEDs were taken during baseline (before perampanel initiation), and at weeks 10, 14, and 19 during the maintenance phase of perampanel treatment (2–12 mg/day, once daily at bedtime). Models estimating apparent clearance of each concomitant AED were fitted to the data, and the effects of perampanel and demographic variables on clearance were determined. Final models were assessed with goodness of fit plots including population predictions and individual predictions against observations.

Results

No significant impact of perampanel on clearance was found for clonazepam (n = 81), levetiracetam (n = 330), phenobarbital (n = 54), phenytoin (n = 90), topiramate (n = 226) or zonisamide (n = 93). Statistically significant, but small and not clinically relevant increases in model‐predicted clearance were detected for carbamazepine (+4.3% with 12 mg perampanel; n = 379), clobazam (+3.4% males, +7.7% females, 12 mg; n = 114), lamotrigine (+9.3%, 12 mg; n = 356), and valproic acid (+5.0%, 12 mg; n = 349). Oxcarbazepine clearance was reduced (26%; n = 200), but the clinical relevance is unclear as levels of the active metabolite (the monohydroxy derivative of oxcarbazepine) were not measured.

Conclusions

Population PK data show that perampanel (2–12 mg/day, once daily at bedtime) has no relevant impact on the clearance of the most commonly used concomitant AEDs.

Long-term efficacy and safety of adjunctive extended-release oxcarbazepine (Oxtellar XR® ) in adults with partial-onset seizures

Objective

To evaluate long‐term outcomes of adjunctive therapy with SPN‐804 (Oxtellar XR^®, Supernus Pharmaceuticals), an extended‐release tablet formulation of oxcarbazepine (OXC), in adults with refractory partial‐onset seizures.

Methods

After completing a 16‐week double‐blind, placebo‐controlled trial of SPN‐804 at fixed dosages (1200 or 2400 mg QD), patients entering this open‐label extension study were converted in blinded fashion to 1200 mg QD SPN‐804 as a target starting dose for long‐term treatment. Patients were followed for 1 year, during which SPN‐804 dosages could be adjusted up to 2400 mg/day according to clinical response.

Results

Of 214 patients, 84% completed 1‐year open‐label treatment. Median maintenance SPN‐804 dosage was 1200 mg; <10% of patients required 2400 mg. Median 28‐day seizure frequency reduction from baseline was 59%; seizure frequency was reduced ≥50% in 58% of patients; 11% were seizure free ≥6 months; and 5% were seizure free ≥1 year. SPN‐804 was discontinued due to adverse events in 5% (n = 10). Incidences of each of the most common adverse events (dizziness, headache, diplopia, nausea, vomiting, balance disorder, blurred vision) were ≤15% during 1‐year follow‐up and occurred most frequently in patients previously naïve to SPN‐804. No new safety signals, no clinically significant changes in health status, and no deaths attributable to SPN‐804 were observed.

Conclusion

SPN‐804 administered once daily for 1 year was effective as adjunctive therapy in improving seizure control and maintaining therapeutic response in adults with refractory partial‐onset seizures. With dosage flexibility, SPN‐804 was well tolerated.

Perspectives on treatment options for mesial temporal lobe epilepsy with hippocampal sclerosis

INTRODUCTION

Mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) is a syndrome that is often refractory to drug treatment. The effects on specific syndromes are not currently available from the pre-marketing clinical development of new AEDs; this does not allow the prediction of whether new drugs will be more effective in the treatment of some patients.

AREAS COVERED

We have reviewed all the existing literature relevant to the understanding of a potential effectiveness in MTLE-HS patients for the latest AEDs, namely brivaracetam, eslicarbazepine, lacosamide, perampanel and retigabine also including the most relevant clinical data and a brief description of their pharmacological profile. Records were identified using predefined search criteria using electronic databases (e.g., PubMed, Cochrane Library Database of Systematic Reviews). Primary peer-reviewed articles published up to the 15 June 2015 were included.

EXPERT OPINION

All the drugs considered have the potential to be effective in the treatment of MTLE-HS; in fact, they possess proven efficacy in animal models; currently considered valuable tools for predicting drug efficacy in TLE. Furthermore, for some of these (e.g., lacosamide and eslicarbazepine) data are already available from post-marketing studies while brivaracetam acting on SV2A like levetiracetam might have the same potential effectiveness with the possibility to be more efficacious considering its ability to inhibit voltage gated sodium channels; finally, perampanel and retigabine are very effective drugs in animal models of TLE.

Psychiatric and behavioral adverse events in randomized clinical studies of the noncompetitive AMPA receptor antagonist perampanel

Objective

Perampanel, a selective, noncompetitive α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) glutamate receptor antagonist, is indicated for adjunctive treatment of partial seizures in patients ≥12 years based on three phase III clinical studies. The perampanel U.S. Prescribing Information includes a boxed warning for serious psychiatric and behavioral adverse reactions. To provide context for this warning, detail on psychiatric and behavioral safety data from perampanel clinical studies is presented.

Methods

An analysis of pooled safety data from three phase III studies in patients with partial seizures is presented. Data from phase I and phase II studies in patients with and without epilepsy were also analyzed. Psychiatric and behavioral treatment‐emergent adverse events (TEAEs) were evaluated according to Medical Dictionary for Regulatory Activities (MedDRA) terms, using “narrow” and “narrow‐and‐broad” standardized MedDRA queries (SMQs) for TEAEs suggestive of hostility/aggression.

Results

From the three phase III partial‐seizure studies, the overall rate of psychiatric TEAEs was higher in the 8 mg (17.2%) and 12 mg (22.4%) perampanel groups versus placebo (12.4%). In the “narrow” SMQ, hostility/aggression TEAEs were observed in 2.8% for 8 mg and 6.3% for 12 mg perampanel groups, versus 0.7% of placebo patients. “Narrow‐and‐broad” SMQs for hostility/aggression TEAE rates were 12.3% for 8 mg and 20.4% for 12 mg perampanel groups, versus 5.7% for placebo; rates for events resulting in discontinuation were perampanel = 1.6% versus placebo = 0.7%. For events reported as serious AEs (SAEs), rates were perampanel = 0.7% versus placebo = 0.2%. In nonepilepsy patients, psychiatric TEAEs were similar between patients receiving perampanel and placebo. In phase I subjects/volunteers, all psychiatric TEAEs were mild or moderate. These analyses suggest that psychiatric adverse effects are associated with use of perampanel.

Significance

Patients and caregivers should be counseled regarding the potential risk of psychiatric and behavioral events with perampanel in patients with partial seizures; patients should be monitored for these events during treatment, especially during titration and at higher doses.

Efficacy and safety of perampanel in adolescent patients with drug-resistant partial seizures in three double-blind, placebo-controlled, phase III randomized clinical studies and a combined extension study

OBJECTIVE

Assess perampanel's efficacy and safety as adjunctive therapy in adolescents (ages 12-17) with drug-resistant partial seizures.

METHODS

Adolescent patients enrolled in multinational, double-blind, placebo-controlled, phase III core studies (studies 304, 305, or 306) completed 19-week, double-blind phase (6-week titration/13-week maintenance) with once-daily perampanel or placebo. Upon completion, patients were eligible for the extension (study 307), beginning with 16-week, blinded conversion, during which placebo patients switched to perampanel. Patients then entered the open-label treatment.

RESULTS

Of 1480 patients from the core studies, 143 were adolescents. Pooled adolescent data from these core studies demonstrated median percent decreases in seizure frequency for perampanel 8 mg (34.8%) and 12 mg (35.6%) were approximately twice that of placebo (18.0%). Responder rates increased with perampanel 8 mg (40.9%) and 12 mg (45.0%) versus placebo (22.2%). Adolescents receiving concomitant enzyme-inducing antiepileptic drugs (AEDs) had smaller reductions in seizure frequency (8 mg:31.6%; 12 mg:26.8%) than those taking non-inducing AEDs (8 mg:54.6%; 12 mg:52.7%). Relative to pre-perampanel baseline, seizure frequency and responder rates during the extension (Weeks 1-52) improved with perampanel. Most commonly reported adverse events in adolescents during the core studies were dizziness (20.4%), somnolence (15.3%), aggression (8.2%), decreased appetite (6.1%), and rhinitis (5.1%). Dizziness (13.2%), somnolence (11.6%), and aggression (6.6%) most often led to perampanel interruption/dose adjustment during the extension.

SIGNIFICANCE

Data demonstrated adjunctive perampanel treatment in adolescents with drug-resistant partial seizures produced better seizure control versus placebo, sustained seizure frequency improvements, and a generally favorable safety profile. Results were comparable to the overall study population.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov Identifiers: Study 304: NCT00699972; 305: NCT00699582; 306: NCT00700310; Study 307: NCT00735397.

Perampanel in the treatment of partial seizures: Time to onset and duration of most common adverse events from pooled Phase III and extension studies

Perampanel (PER) is a novel noncompetitive AMPA-receptor antagonist approved in over 40 countries for treatment of partial seizures. The safety and tolerability of PER have been well-documented in three double-blind, randomized, placebo (PBO)-controlled Phase III studies and an open-label extension (OLE). This post hoc analysis evaluated the occurrence and characteristics of the most common treatment-emergent adverse events (TEAEs) associated with PER. Results from the Phase III studies were pooled; post hoc analyses on the double-blind phase and up to 1 year of the OLE were performed on the four most common TEAEs for which incidence was higher for PER than PBO. The four most common TEAEs were dizziness, somnolence, fatigue, and irritability. For most subjects in the Phase III double-blind studies, these TEAEs were observed during 6-week titration and were mild or moderate in severity. For severe AEs, no dose-response relationship was observed. Patients in the PBO group during Phase III (who therefore received their first PER treatment during OLE) experienced these TEAEs with incidence and timing similar to that of PER-treated patients in Phase III. The first onset of these TEAEs occurred during the early weeks of PER conversion in the OLE. After 6months and up to 1 year of PER treatment, low to no incidence of the first onset of the four TEAEs was observed. Post hoc analyses of data from pooled Phase III studies provide greater insight into occurrence/duration of TEAEs. Phase III double-blind and OLE data showed that dizziness, somnolence, fatigue, and irritability were the most common TEAEs reported by patients taking PER. Additionally, these results suggest consistency between studies in patient responses to onset of these TEAEs. Although concomitant antiepileptic drugs (AEDs) might be predicted to affect development of TEAEs in patients taking PER, an effect was not observed in this analysis. The low incidence of TEAEs in these studies provides additional support for long-term PER treatment.

The AMPA receptor antagonist perampanel in the adjunctive treatment of partial-onset seizures: clinical trial evidence and experience

More than 20 antiepileptic drugs (AEDs) are currently available for the medical treatment of epilepsies. However, still about 30% of all epilepsies have a drug-resistant course. Even worse, in the case of some epilepsy syndromes, freedom from seizures is almost never achieved. Therefore, new treatment options are still necessary, especially if theoretical concepts such as a new mode of action offer new horizons. Perampanel is the first-in-class orally active, selective, noncompetitive antagonist of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The pharmacokinetic profile offers once-daily dosing in the evening as the best route of administration. According to the results of three pivotal placebo-controlled, double-blind phase III trials that investigated perampanel as an adjunctive AED in adult and adolescent patients from age 12 years who had ongoing focal epileptic seizures despite receiving one to three AEDs, perampanel has been widely licensed and introduced. Phase III trials showed superiority of adjunctive perampanel over placebo consistently in the range between 4 and 12 mg. Dizziness and somnolence were by far the leading adverse events. This review covers the clinical trial evidence but also clinical experience with perampanel after launch according to observational studies.

Long-term treatment with responsive brain stimulation in adults with refractory partial seizures

OBJECTIVE

The long-term efficacy and safety of responsive direct neurostimulation was assessed in adults with medically refractory partial onset seizures.

METHODS

All participants were treated with a cranially implanted responsive neurostimulator that delivers stimulation to 1 or 2 seizure foci via chronically implanted electrodes when specific electrocorticographic patterns are detected (RNS System). Participants had completed a 2-year primarily open-label safety study (n = 65) or a 2-year randomized blinded controlled safety and efficacy study (n = 191); 230 participants transitioned into an ongoing 7-year study to assess safety and efficacy.

RESULTS

The average participant was 34 (±11.4) years old with epilepsy for 19.6 (±11.4) years. The median preimplant frequency of disabling partial or generalized tonic-clonic seizures was 10.2 seizures a month. The median percent seizure reduction in the randomized blinded controlled trial was 44% at 1 year and 53% at 2 years (p < 0.0001, generalized estimating equation) and ranged from 48% to 66% over postimplant years 3 through 6 in the long-term study. Improvements in quality of life were maintained (p < 0.05). The most common serious device-related adverse events over the mean 5.4 years of follow-up were implant site infection (9.0%) involving soft tissue and neurostimulator explantation (4.7%).

CONCLUSIONS

The RNS System is the first direct brain responsive neurostimulator. Acute and sustained efficacy and safety were demonstrated in adults with medically refractory partial onset seizures arising from 1 or 2 foci over a mean follow-up of 5.4 years. This experience supports the RNS System as a treatment option for refractory partial seizures.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for adults with medically refractory partial onset seizures, responsive direct cortical stimulation reduces seizures and improves quality of life over a mean follow-up of 5.4 years.

Perampanel in the management of partial-onset seizures: a review of safety, efficacy, and patient acceptability

Perampanel (PER) is a novel antiepileptic drug recently introduced for the adjunctive treatment in epilepsy patients aged 12 years or older with partial-onset seizures with or without secondary generalization in the US and Europe. Its antiepileptic action is based on noncompetitive inhibition of postsynaptic AMPA receptors, decreasing excitatory synaptic transmission. Evaluation of efficacy in three placebo-controlled randomized Phase III studies showed that add-on therapy of PER decreased seizure frequencies significantly compared to placebo at daily doses between 4 mg/day and 12 mg/day. PER's long half-life of 105 hours allows for once-daily dosing that is favorable for patient compliance with intake. Long-term extension studies showed a 62.5%-69.6% adherence of patients after 1 year of treatment, comparing favorably with other second-generation antiepileptic drugs. Whereas these trials demonstrated an overall favorable tolerability profile of PER, nonspecific central nervous system adverse effects like somnolence, dizziness, headache, and fatigue may occur. In addition, neuropsychiatric disturbances ranging from irritability to suicidality were reported in several case reports; both placebo-controlled and prospective long-term extension trials showed a low incidence of such behavioral and psychiatric complaints. For early recognition of neuropsychiatric symptoms like depression, anxiety, and aggression, slow titration and close monitoring during drug introduction are mandatory. This allows on the one hand to recognize patients particularly susceptible to adverse effects of the drug, and on the other hand to render the drug's full potential of seizure control available for the vast majority of patient groups tolerating the drug well.

Perampanel: a significant liver enzyme inducer in some patients?

Perampanel is one of the latest released antiepileptic drugs (AEDs). Early studies suggest no significant liver enzyme induction from this compound. We report on two patients with medically resistant epilepsy, who had perampanel added to their usual regimen. Both experienced a worsening of their epilepsy and presented in convulsive status epilepticus; concurrent antiepileptic drug levels (phenytoin, phenobarbital, rufinamide) were significantly decreased (<50%) in comparison with levels prior to perampanel introduction. Intravenous load and significant increase of maintenance dosages were needed to restore therapeutic drug levels. In one patient, further increase of perampanel resulted in a new drop of phenytoin level. This suggests that perampanel could, in some subjects, induce liver enzymes and interact with concomitant AEDs; monitoring levels of concomitant compounds could be useful.